Sedative
Etymology
From Latin “sedare” (to settle or calm), the causative of “sedēre” (to sit) — so a sedative literally makes you sit down and settle. Medieval Latin “sedativus” carried the sense into medicine. The buried image is bodily and homely: agitation stilled the way a person is eased into a chair.
noun · /SED-uh-tiv/
A drug that calms agitation and induces drowsiness by slowing down the nervous system.
What it names
The class of substances that dial the body down rather than up — the pharmacological opposite of a stimulant, and the thing meant when someone is “given something to relax.”
Example
They gave him a mild sedative before the MRI because he could not stay still inside the scanner.
Related idea
A sedative slows the nervous system down; a stimulant speeds it up. Both are defined by direction of effect rather than chemistry, so caffeine and cocaine share a category, as do a nighttime antihistamine and a surgical tranquillizer.